Degradation of Indoor Ammonia Using TiO2 Thin Film Doped with Iron(III) under Visible Light Illumination

2013 ◽  
Vol 668 ◽  
pp. 136-139
Author(s):  
Shuai Jie Wang ◽  
Hao Yu ◽  
Xue Qin Gao

A type of titania thin film doped with iron(III) was prepared by means of sol-gel method to degrade indoor ammonia (NH3) under visible light irradiation. The photocatalysts was characterized by X-ray diffraction (XRD) and UV-vis spectroscopy. The results demonstrated that the adsorption edge of doped TiO2 thin film had red shifts and the doped TiO2 thin film had a stronger absorption than undoped TiO2 thin film in the visible region. Doping amount of Fe(III) effected the photocatalytic actitivity of Fe-doped TiO2 thin film significantly. The optimal doping amount of Fe(III) was 1%(mole fraction). Using the optimal Fe-doped TiO2 thin film, the removal percentage of NH3 after 9h phtocatalytic reaction under visible light reached 53.1%. The degradation reaction of NH3 was successfully described by the pseudo first-order kinetics. The reaction rate constant decreased with the increase of initial concentration of NH3, which reflected that there was oxidation competition between NH3 and its intermediate during the photocatalytic process.

2009 ◽  
Vol 79-82 ◽  
pp. 2127-2130 ◽  
Author(s):  
Song Tao Gu ◽  
Xin Wang ◽  
Qiang Liu ◽  
Hao Quan Liu ◽  
Gui Jun Jiang ◽  
...  

A visible-light-active nitrogen and gadolinium codoped TiO2 catalyst was synthesized by the sol-gel route. For comparison, Gd-doped sample, N-doped sample, and pure titania were prepared through the same method, without adding the corresponding dopants. The as-prepared photocatalysts were characterized by X-ray diffraction (XRD) and Uv-vis spectra. The results showed that the codoped photocatalyst exhibited a smaller size than the undoped titania. The transformation from anatase to rutile was suppressed by doping with N and Gd atoms. Furthermore, the absorbance spectra of N, Gd-codoped TiO2 exhibited a significant red shift to the visible region. The photocatalytic activity of N, Gd-codoped TiO2 was evaluated by photodegradation of methyl orange under visible light irradiation. This codoped sample exhibited enhanced photocatalytic activity compared to N-doped TiO2, Gd-doped TiO2, and pure TiO2. The improvement of the photocatalytic activity was ascribed to the synergistic effects of the N and Gd co-doping.


Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 235
Author(s):  
Hayette Benkhennouche-Bouchene ◽  
Julien G. Mahy ◽  
Cédric Wolfs ◽  
Bénédicte Vertruyen ◽  
Dirk Poelman ◽  
...  

TiO2 prepared by a green aqueous sol–gel peptization process is co-doped with nitrogen and zirconium to improve and extend its photoactivity to the visible region. Two nitrogen precursors are used: urea and triethylamine; zirconium (IV) tert-butoxide is added as a source of zirconia. The N/Ti molar ratio is fixed regardless of the chosen nitrogen precursor while the quantity of zirconia is set to 0.7, 1.4, 2, or 2.8 mol%. The performance and physico-chemical properties of these materials are compared with the commercial Evonik P25 photocatalyst. For all doped and co-doped samples, TiO2 nanoparticles of 4 to 8 nm of size are formed of anatase-brookite phases, with a specific surface area between 125 and 280 m2 g−1 vs. 50 m2 g−1 for the commercial P25 photocatalyst. X-ray photoelectron (XPS) measurements show that nitrogen is incorporated into the TiO2 materials through Ti-O-N bonds allowing light absorption in the visible region. The XPS spectra of the Zr-(co)doped powders show the presence of TiO2-ZrO2 mixed oxide materials. Under visible light, the best co-doped sample gives a degradation of p-nitrophenol (PNP) equal to 70% instead of 25% with pure TiO2 and 10% with P25 under the same conditions. Similarly, the photocatalytic activity improved under UV/visible reaching 95% with the best sample compared to 50% with pure TiO2. This study suggests that N/Zr co-doped TiO2 nanoparticles can be produced in a safe and energy-efficient way while being markedly more active than state-of-the-art photocatalytic materials under visible light.


2019 ◽  
Vol 8 (4) ◽  
pp. 6994-7000

This research study aims at fabrication of fine size nitrogen doped TiO2 nanofiber using electrospinning method and evaluation of the performance of TiO2 in a photovoltaic cell under visible light irradiation. Undoped and N doped TiO2 nanoparticles were synthesized by sol gel method where titanium isopropoxide was used as the source of TiO2 and ammonium nitrate was used as the source of N dopant. TiO2 /PVA composite material was prepared by stabilizing TiO2 particle in to 10 wt % of PVA (aq) solution in order to prepare thin film that can be coated on photovoltaic (PV) cells. Coating of solid thin film PV cells by TiO2 /PVA nanofibers was conducted using electrospinning and doctor blade method. In both systems, doping the TiO2 with nitrogen improved its optical properties which it successfully lowered the band gap energy from 3.14 to 2.76 eV and shifted its optical response to the visible light region. The presence of O-H stretching vibration, O-H bending and vibration of the N-Ti bond contributed to an increased performance of the PV cells. The electrospun N-doped TiO2 produced better power output than doctor blade method coated PV cells with power of 0.040 and 0.026 mW, respectively.


Author(s):  
Jutarat Kwakkaew ◽  
Matthana Khangkhamano ◽  
Rungrote Kokoo ◽  
Weerachai Sangchay

TiO2-based nanomaterials have been extensively synthesized and used in a wide range of photocatalytic applications. The photocatalytic oxidation process, however, is only activated by irradiation with ultraviolet (UV) light which limits its indoor applications. Herein, to improve such limitations, N/Li2MoO4-doped TiO2 nanoparticles were prepared via sol-gel method. Li2MoO4 concentration was varied. The catalysts were characterized by XRD, XPS, FE-SEM, and UV-Vis spectroscopy. As-synthesized N/Li2MoO4-doped TiO2 catalysts exhibited their crystal sizes of as fine as 20 nm in diameter whereas that of the pure TiO2 was about 35 nm. The absorption ranges of the N/ Li2MoO4-doped catalysts were relocated from UV region toward visible light region. The catalyst with 1 mol% Li2MoO4 offered the highest degradation rate of methylene blue (MB) solution upon visible light irradiation. Its fine crystal size, narrow band gap energy (2.82 eV), high defect concentration, and strong light absorption in visible region are responsible for the enhanced photocatalytic activity of the 1 mol% Li2MoO4.


2010 ◽  
Vol 434-435 ◽  
pp. 847-849
Author(s):  
Le Fu Mei ◽  
Kai Ming Liang

The Mg-doped TiO2 was prepared by Sol-gel method at low temperature. The crystallization of TiO2 was studied by DTA, it was shown that the phase transition temperature of the Mg (NO3)2-doped TiO2 from amorphous to anatase and then to rutile significantly reduce. The XRD results show that the Mg-doped TiO2 has anatase and rutile annealed at 600 °C. Studies of photo-catalytic degradation show that the photo-catalytic activity of Mg-doped TiO2 thin film is higher than that of non-doped TiO2.


2017 ◽  
Vol 9 (2) ◽  
pp. 6
Author(s):  
Diana Vanda Wellia

The photocatalytic properties of TiO2 compound in anatase phase can be activated under visible light by nitrogen modification and its ability can be increased by generated porous structure using polietilen glikol (PEG) on TiO2 thin film surface. The porous N/TiO2 thin films were prepared by heating aqueous peroxotitanate thin films by addition of polietilen glikol (PEG) deposited uniformly on superhydrophilic uncoated glass at 500 oC for 1 h. The result of X-ray diffraction (XRD) confirmed the resence of only anatase phase for all samples. The UV-Vis spectroscopy showed the synthesized porous N/TiO2 thin films exhibit the absorption in the visible range (400-500 nm). Photocatalytic activity of porous N/ TiO2 thin films were evaluated by using fourier transform-infrared spectroscopy (FTIR) to determine the ability of this photocatalyst for stearic acid degradation under visible light irradiation. The result showed that N/TiO2/PEG-2.1 thin film degraded the stearic acid was about 87,86%, which was 1,12 times higher than that of N-doped TiO2 and 9,9 times higher than that of undoped TiO2 thin film.


2015 ◽  
Vol 2015 ◽  
pp. 1-6
Author(s):  
Shuaijie Wang ◽  
Xingxing Cheng

A type of iron and nitrogen codoped titania thin film was prepared by sol-gel method to degrade three typical indoor air pollutants: formaldehyde (HCHO), ammonia (NH3), and benzene (C6H6) under solar light. X-ray diffraction (XRD), UV-Vis spectroscopy, and energy dispersive spectra (EDS) were employed to characterize the photocatalysts. The results showed that the Fe/N codoped TiO2had a stronger absorption in the visible region than pure, Fe-doped, and N-doped TiO2and exhibited excellent photocatalytic ability for the degradation of indoor HCHO, NH3, and C6H6. When the three pollutants existed in indoor air at the same time, the removal percentages of HCHO, NH3, or C6H6after 6 h photocatalytic reaction under solar light reached 48.8%, 50.6%, and 32.0%. The degradation reaction of the three pollutants followed the pseudo-first-order kinetics with the reaction rate constants in the order of 0.110 h−1for ammonia, 0.109 h−1for formaldehyde, and 0.060 h−1for benzene. The reaction rate constant decreased with the increase of initial reactant concentration, which reflected that there was oxidation competition between the substrate and its intermediate during the photocatalytic process.


2014 ◽  
Vol 2014 ◽  
pp. 1-5
Author(s):  
Shuaijie Wang ◽  
Hao Yu ◽  
Xingxing Cheng

A type of iron-doped titania thin film was prepared by means of sol-gel method to degrade indoor formaldehyde (HCHO), ammonia (NH3), and benzene (C6H6) under sunlight. The photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-Vis spectroscopy, and energy dispersive spetra (EDS). The results showed that the iron was doped in the TiO2photocatalyst successfully. The absorption edge of doped TiO2had red shifts and the doped TiO2had a stronger absorption than the pure TiO2in the visible region. Fe-doped TiO2thin film prepared with the optimal preparation condition could remove indoor HCHO, NH3and C6H6effectively under solar light irradiation. The removal percentage of HCHO, NH3or C6H6after 9 h photocatalytic reaction under solar light reached 55%, 53.1%, and 37.5%, respectively, when they existed in the air individually. When the three pollutants were mixed in the air, the removal percentage decreased to 33.3%, 28.3%, and 28%. The degradation reaction of the three pollutants followed the pseudo first-order kinetics, which reflects that the photocatalytic reaction was controlled by the surface chemical reaction and the reaction rate was controlled by concentration of reactants.


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